The present invention relates to power contacts and a receiving contactor, and more particularly relates to adjustments which may be made to the contacts or contactor within the field.
Contactors for motor, lighting, and general purpose applications are generally designed with one or more power contacts. These contacts change state when the contactor is energized. As new circuits are added, new poles must be added to the contactor. Manufacturers have solved this problem by offering contactors with 2 to 12 poles. All these contactors are designed with a common base that is manufactured for a specific number of contacts. Contacts cannot be added in the field without disassembling the contact, if it is even possible at all. Today, the quantity of contacts in a multi-pole contactor must be selected before the unit is shipped from the factory. As a result of this, contactors cannot be upgraded in the field to add poles when the application requires. This also results in a significant inventory of finished goods.
To solve the above-described problem, some manufacturers have produced single adder poles which can be assembled to a 3 or 4 pole frame to add one pole. These adder pole kits often require the complete disassembly of the contactor and the replacement of several parts. Some adder pole kits are restricted to low power contact blocks and often only for control functions.
It is common practice to use multiple normally open and normally closed contacts within a contactor. A distributor would not normally know the exact configuration of normal open and normal closed poles when the contactor is ordered. Today, the function of contacts in a multi-pole contactor must be selected before the unit is shipped from the factory. As a result of this, when the function of the contact needs to be changed, the contactor must be completely disassembled to make a change. This also adds significant material cost because contacts must be included for both forms of contacts with every unit.
To solve the above described problem, some manufacturers use symmetrical contacts, which can be changed from normal open to normal closed and back by completely disassembling the unit and reversing the springs and parts. Also, low power level contacts are sometimes designed in modular units, which can be replaced to provide contact form change.
Lighting contactors are either electrically or mechanically held contactors used to control lighting in commercial and industrial applications. Today, a customer must purchase two different products, which are not easily interchangeable to serve both applications. This also enables the customer to manually operate the contactor in the event of a control power circuit failure. Also, the manufacturer, distributor, and installer must inventory two different products for mechanically and electrically held applications. This drives significant manufacturing cost due to the reduced volume in each line, and cost of inventory. In addition, since the two products are dissimilar, they are not interchangeable in the field, increasing the cost of future retrofit.
To solve the above-described problem, some manufacturers provide an accessory that can be applied to a contactor to mechanically latch the contactor. Although this solves the problem, often the height of the contactor is significantly increased, because this design utilizes a second coil. The second coil also reduces the reliability of the design and adds to the cost and weight of the contactor.
In an exemplary embodiment of the invention, a contactor for receiving contact modules and a contact module receivable in the contactor includes a contactor having a cover, the cover having cam openings, each cam opening providing access to first and second cam profiles raised from first and second sides of a flat surface, respectively, each cam profile including a raised surface and a sloped surface connecting the raised surface to the flat surface.
The contact module receivable on the contactor preferably includes a housing, a stationary contact positioned within the housing, a spring-biased cam follower protruding from the housing, a spring for biasing the cam follower, a plunger extending from the cam follower and through the housing, the plunger movable with the cam follower, a module plate extending from the plunger, the module plate movable with the plunger and cam follower, a movable contact on the module plate, the movable contact movable with the module plate, wherein the cam follower is movable along its longitudinal axis from a first position where the movable contact abuts the stationary contact to a second position where the movable contact is separated from the stationary contact.
Initially positioning the cam follower of the contact module upon the first cam profile in the contactor results in a normally closed contact module with the cam follower placed on a raised surface forcing the cam follower into the second position, and initially positioning the cam follower of the contact module upon the second cam profile results in a normally open contact module with the cam follower resting on a flat surface and allowing the cam follower to be in the first position.
The contactor may additionally include a latch assembly for mechanically holding the contactor during de-energization of the contactor, the latch assembly preferably including a latching bar having a first end and a second end, a latch plunger, the latch plunger having a head portion, a neck portion, and main body portion, the head portion of the latch plunger for connecting with a connector extending from an electromagnetically driven portion of the contactor, the neck portion of the latch plunger having a slot for receiving the first end of the latching bar, the main body portion containing a closed loop pathway for receiving the second end of the latching bar, and a latch assembly base and a latch assembly cover forming a chamber for receiving the latch plunger therein, the latch plunger slidable from a bottom end to a top end of the chamber. The first end of the latching bar extends through an opening in the latch assembly cover and the second end of the latching bar extends through an aperture in the latch assembly cover.